﻿using System.Web;
using System.Text;
using System.Security.Cryptography;
using System.IO;
using System.Net;
using System;
using System.Collections.Generic;
using System.Xml;

/// <summary>
/// 功能：支付宝接口公用函数类
/// 详细：该类是请求、通知返回两个文件所调用的公用函数核心处理文件，不需要修改
/// </summary>
public class AlipayCore
{
    public AlipayCore()
    {
 
    }

    /// <summary>
    /// 生成签名结果
    /// </summary>
    /// <param name="sArray">要签名的数组</param>
    /// <param name="key">安全校验码</param>
    /// <param name="sign_type">签名类型</param>
    /// <param name="_input_charset">编码格式</param>
    /// <returns>签名结果字符串</returns>
    public static string BuildMysign(Dictionary<string, string> dicArray, string key, string sign_type, string _input_charset)
    {
        string prestr = CreateLinkString(dicArray);  //把数组所有元素，按照“参数=参数值”的模式用“&”字符拼接成字符串

        prestr = prestr + key;                      //把拼接后的字符串再与安全校验码直接连接起来
        string mysign = Sign(prestr, sign_type, _input_charset);	//把最终的字符串签名，获得签名结果

        return mysign;
    }

    /// <summary>
    /// 除去数组中的空值和签名参数并以字母a到z的顺序排序
    /// </summary>
    /// <param name="dicArrayPre">过滤前的参数组</param>
    /// <returns>过滤后的参数组</returns>
    public static Dictionary<string, string> FilterPara(SortedDictionary<string, string> dicArrayPre)
    {
        Dictionary<string, string> dicArray = new Dictionary<string, string>();
        foreach (KeyValuePair<string, string> temp in dicArrayPre)
        {
            if (temp.Key.ToLower() != "sign" && temp.Key.ToLower() != "sign_type" && temp.Value != "" && temp.Value != null)
            {
                dicArray.Add(temp.Key.ToLower(), temp.Value);
            }
        }

        return dicArray;
    }

    /// <summary>
    /// 把数组所有元素，按照“参数=参数值”的模式用“&”字符拼接成字符串
    /// </summary>
    /// <param name="sArray">需要拼接的数组</param>
    /// <returns>拼接完成以后的字符串</returns>
    public static string CreateLinkString(Dictionary<string, string> dicArray)
    {
        StringBuilder prestr = new StringBuilder();
        foreach (KeyValuePair<string, string> temp in dicArray)
        {
            prestr.Append(temp.Key + "=" + temp.Value + "&");
        }

        //去掉最後一個&字符
        int nLen = prestr.Length;
        prestr.Remove(nLen - 1, 1);

        return prestr.ToString();
    }

    /// <summary>
    /// 签名字符串
    /// </summary>
    /// <param name="prestr">需要签名的字符串</param>
    /// <param name="sign_type">签名类型</param>
    /// <param name="_input_charset">编码格式</param>
    /// <returns>签名结果</returns>
    public static string Sign(string prestr, string sign_type, string _input_charset)
    {
        StringBuilder sb = new StringBuilder(32);
        if (sign_type.ToUpper() == "MD5")
        {
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] t = md5.ComputeHash(Encoding.GetEncoding(_input_charset).GetBytes(prestr));
            for (int i = 0; i < t.Length; i++)
            {
                sb.Append(t[i].ToString("x").PadLeft(2, '0'));
            }
        }
        return sb.ToString();
    }

    /// <summary>
    /// 写日志，方便测试（看网站需求，也可以改成把记录存入数据库）
    /// </summary>
    /// <param name="sWord">要写入日志里的文本内容</param>
    public static void LogResult(string sWord)
    {
        string strPath = HttpContext.Current.Server.MapPath("log");
        strPath = strPath + "\\" + DateTime.Now.ToString().Replace(":", "") + ".txt";
        StreamWriter fs = new StreamWriter(strPath, false, System.Text.Encoding.Default);
        fs.Write(sWord);
        fs.Close();
    }
}
